Anatomy Lab 7
Overview of the skeleton: classification and structure of bones and cartilages.
Overview of the skeleton: classification and structure of bones and cartilages.
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Flashcards
What are osteoblasts?
bone forming cells.
What are osteoclasts
bone destroying cells found in the inner, or osteogenic layer of the periosteum.
What is the epiphysis?
The end of the long bone - composed of a thin layer of compact bone that encloses spongy bone.
What is the articular cartilage?
Cartildge that covers the epiphyseal surface in place of the periosteum of the long bone. It's a glassy hyaline cartilage that provides a mooth surface to minimize friction at the joints.
What is the epiphyseal plate?
Present in the long bones of young and growing animals - a thin area of hyaline cartilage that provides for longitudinal growth of the bones during youth.
What is epiphyseal plate replaced with when the bone has stopped growing?
Epiphyseal lines - very thin and basically invisible.
What is Yellow Marrow?
It's a type of marrow in the long bone that is in the central cavity of the shaft, it is a storage region for adipose tissue.
What is red marrow?
involved in forming blood cells, in adults it's confined to the interior of the epiphyses, where it occupies the spaces between the traceculae of spongy bone.
what is the endosteum lining?
It lines the shaft of the long bone - very delicate. It covers the trabeculae of spongy bone and lines the canals of compact bone. Like the periosteum, the endosteum contains both osteoblasts and osteoclasts. As the bone grows in diameter on its external surface, it is constantly being broken down on its inner surface. This keeps the thickness of the bone layer composing the shaft constant.
What causes the hardness of bones?
Calcium salts deposited in its ground substance.
What causes the flexibility of bones?
the organic elements of the matrix, particularly the collagen fibers.
What is bone tissue organized around?
It's blood supply.
What is the central (haversian) canal?
It's a central canal that runs parallel to the long axis of the bone and carries blood vessels, nerves, and lymphatic vessels through the bony matrix ... found in the compact bone of long bones.
What are osteocytes?
mature bone cells.
Where are osteocytes found?
in the lacunae where are arranged in concentric circles.
What are concentric lamellae?
Concentric circles of lacunae around the central canal of the long bone.
What is an osteon?
Also called a Harversian system - it's composed of a central canal and all the concentric lamellae srrounding it in the compact bone.
What are canaliculi?
Tiny canals radiating outward from a central canal to the lacunae of the first lamella and then from lamella to lamella. They form a dense transportation network through the hard bone matrix, connecting all the living cells of the osteon to the nutrient supply. They allow each cell to take what it needs for nourishment and to pass along the excess to the next osteocyte. In the compact bone of the long bone.
What are perforating canals?
Also known as volkmann's canals - run at right angles to the shaft and complete the communication pathway between the bone interior and its external surface.
what are the seven major locations of cartilidge in the skeleton?
1. articular cartilages - cover the bone ends at movable joints
2. costal cartilages - found connecting the ribs to the sternum (breastbone)
3. Laryngeal cartilages - largely construct the larynx (voice box)
4. Tracheal and bronchial cartilages - reinforce the other passageways of the respiratory system.
5. nasal cartilages - support the external nose.
6. intervertebral discs - separate the cushion bones of the spine.
7. the cartilage supporting the external ear.
What is the surrounding layer of cartilidge?
Perichondrium - acts like a girdle to resist distortion of the cartilage when the cartilage is subjected to pressure. Also plays a role in cartilage growth and repair.
What are the three types of cartilidge present in the skeletal system?
Hyaline, Elastic, Fibrocartilage.
Describe skeletal Hyaline Cartilage
Looks like frosted glass when viewed by the unaided eye. Most skeletal cartilages are composed of hyaline cartilage. Provides sturdy support with some resilience or "give."
Describe Elastic Cartilage.
can be envisioned as "hyaline cartilage with more elastic fibers." consequently it is much more flexible than hyaline cartilage, and it tolerates repreated bending better. Eseentially, only the cartilages of the external ear and the epiglottis (which flops over and covers the larynx when we swallow) are made of elastic cartilage.
Describe fibrocartilage.
Consists of rows of chondrocytes alternating with rows of thick collagen fibers. This tissue looks like a cartilage-dense regular connective tissue hybrid. Fibrocartilage has great tensile strength that can withstand heavy compression. Hence, its use to constrauct the intervertebral discs and the cartilages within the knee joint makes a lot of sense.
